This contract is designed to evaluate experimental HIV vaccine strategies in non-human primates before these vaccines would proceed into clinical trials. Vaccines will be tested for safety and immunogenicity. Challenge studies using Simian Immunodeficiency Virus (SIV) or chimeric HIV/(SIV (SHIV) viruses will also be performed. Vaccine strategies investigated will include nucleic acid vaccines, recombinant proteins, whole-killed and attenuated viral vaccines as well as immunologic adjuvants and antigen delivery systems.